Gene-Based Therapy May Thwart a Tough Blood Cancer

MONDAY, June 5, 2017 (HealthDay News) -- Genetically tuning a person's own immune cells to target cancer appears to provide long-lasting protection against a blood cancer called multiple myeloma, an early trial from China shows.

The treatment, called CAR T-cell therapy, caused 33 out of 35 patients with recurring multiple myeloma to either enter full remission or experience a significant reduction in their cancer.

The results are "impressive," said Dr. Len Lichtenfeld, deputy chief medical officer for the American Cancer Society.

"These are patients who have had prior treatment and had their disease return, and 100 percent of the patients are reported to have had some form of meaningful response to these cells that were administered," Lichtenfeld said.

The new therapy is custom-made for each patient. Doctors collect the patient's own T-cells -- one of the immune system's main cell types -- and genetically reprogram them to target and attack abnormal multiple myeloma cells.

Lead researcher Dr. Wanhong Zhao likened the process to fitting immune cells with a GPS that steers them to cancer cells -- making them into professional killers that never miss their target.

Zhao is associate director of hematology at the Second Affiliated Hospital of Xi'an Jiaotong University in Xi'an, China.

CAR T-cell therapy is promising because the genetically altered T-cells are expected to roost in a person's body, multiplying and providing long-term protection, Lichtenfeld said.

"The theory is they should attack the tumor and continue to grow to become a long-term monitoring and treatment system," Lichtenfeld said. "It's not a one-shot deal."

The technology represents the next step forward in immunotherapy for cancer, said Dr. Michael Sabel, chief of surgical oncology at the University of Michigan.

"Immunotherapy is now really providing hope to a lot of patients with cancers that were not really responding to our standard chemotherapies," Sabel said.

CAR T-cell therapy previously has been used to treat lymphoma and lymphocytic leukemia, Lichtenfeld said.

Zhao and his colleagues decided to try the therapy to treat multiple myeloma. They re-engineered the patients' T-cells and then reintroduced them to the body in three infusions performed within one week.

Continued

Multiple myeloma is a cancer that occurs in plasma cells, which are mainly found in bone marrow and produce antibodies to fight infections. About 30,300 people will likely be diagnosed with multiple myeloma this year in the United States, researchers said in background notes.

"Multiple myeloma is a disease that historically was fatal in the course of a couple of years," Lichtenfeld said. During the past two decades, new breakthroughs have extended survival out 10 to 15 years in some patients, he noted.

To date, 19 of the first 35 Chinese patients have been followed for more than four months, researchers report.

Fourteen of those 19 patients have reached the highest level of remission, researchers report. There hasn't been a relapse among any of these patients, including five followed for more than a year.

"That's as far as you can go in terms of driving down the amount of tumor that's in the body," Lichtenfeld said.

Out of the remaining five patients, one experienced a partial response and four a very good response, researchers said.

However, about 85 percent of the patients experienced cytokine release syndrome (CRS), a potentially dangerous side effect of CAR T-cell therapy.

Symptoms of cytokine release syndrome can include fever, low blood pressure, difficulty breathing, and impaired organ function, the researchers said. However, most of the patients experienced only transient symptoms, and "now we have drugs to treat it," Lichtenfeld said.

History suggests the therapy will cost a lot if it receives approval, Lichtenfeld said. However, prior to approval, much more research will be needed, he added.

The Chinese research team plans to enroll a total of 100 patients in this clinical trial at four hospitals in China. They also plan a similar clinical trial in the United States by 2018, Zhao said.

The study was funded by Nanjing Legend Biotech Co., the Chinese firm developing the technology.

The findings were presented Monday at the American Society of Clinical Oncology annual meeting, in Chicago. Data and conclusions presented at meetings are usually considered preliminary until published in a peer-reviewed medical journal.